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mate-s Patent 23 2*,731 471 .znnnazomsnnaswa vs wrsahyunazsanta Barbara, "iflalifl, assignors ,ato l-tMel ille The "present invention irfelatjes to chemical, compounds ncerned' With (it) 'TZSKhYdrosand is more particulaily carbonl-iniidazolines"hay ngth f 1.? l l 2: #(t'JH whereinn :isnthe :integerttwomr fthreqr and (1b) acid adjdirtlon and: quaternary ammoniuntzsaltsithereof.

his application 'ris ia a continuation-impart of our prior -filed aPPlicationrSerial 3.61; 819Qfiled li'1ne 15,1953, now it abandoned.

The compounds of .thetpresent invention have pharmacological 4 properties which indicate ithatthey-are potent -pressor materials.withsa-irelatively low toxicity, ahigh :therapeutic index, .Iand. :relatively long-ipcriod 3 of {therapeutic effect. The HCIdaddlIlOH- Q d quaternary-am- -mom'um salts areacrystalline =solids hai ihg high melting points andare soluble in water. The free imidazolines example, the methyl ester, ethyl ester,propyl ester, iso- 45 propyl ester, butyl ester, pentyl ester, hexyl ester, et cetera. This 1 reaction is usually coniiucted by heatingtthc 'ethylenedianiine toabout its' r'fiuxtemperature and add ing appropriate acid or ester to the *boiliiggfliquiil with subsequent heating at reflux "for a "suitable time. It is to be understood, however, that other temperaturesmay' be used, --With a conseguent increase "or decrease in reaction time, dependingon the partictiiar ternperatureand 1 reacting 1 components used. Equimdlecularquantities .of

reactants are satisfactory, although an'exccss'dfthe'e'thyl- 'enediamine -is'preferred. Upon "completion 'of the reaction, the reaction mixture is cooled, and thefsnbsti- "tuted imidazoline separated in conventional "manner.

A preferred procedure for preparingi'the"compounds contemplates the condensation 'of -tire"mono para-toluenesulfonate salt of ethylenediamine with l.,2,3 ,4-tetrahydro 1maphthonitrile or "-l=indanecarbonitrile This reaction is conducted similar to the condensationdescribed above, 'and the product separated in conventional rnanner.

Acid addition salts, such as, for example;"the tartrate, nitrate, sulfate, hydrochloride, rhydrobromide, hydriodide, acetate, et cetera, and quaternaryammonium salts such as, for example, the -ilirnethylsulfate, -'ethyl bromide, 'rmethiodide, propyl chloride, et, cetera, may be prepared Lby :contacting: an ethereal; solution uftthe free im'idazoline resulting salt,

T35 the methyl .alcohol. toflthe present inventionare ery'stalline solidsgsoluble'in .40 Example 2,73 1,4 71 Pat nted Jan. 17, ,1956

The"following,preparations are given to-tillustrate the preparationtof, intermediates useful inathe preparation sol the? compounds ofqthe present invention.

5 Preparation 1.],2,3,4-tetrdhydrq-l-rmphthonitrile --Mar'tin E. Synerholm laeonard .fltiJules and Melville Twenty-eight (2 8.Q) grams (0.l6.mole) of l,2, 3,4- tetrahy'clro-l naphthoamide, fifty milliliters of .thionyl chloride and fifty milliliters of benzene .were heated together.under,refl,ux "lfor sixfhours. After removing-a small amount of solid materialbyfiltration, the solvent and excess thionyl chloride were removed by'distillation under-a reduced; pressure of about seven millimeters. of mercury absolute. There was thus obtained 19.5 grams -(77.-5-percent of thelt'theoretical,yield) of l, 2,3',4-tetra-- 5 thydro-l-n'aphthonitrile, boiling at 135-137 degrees centi- -grade at seven millimeters of mercury pressure absolute. vAnalysis.Calculated for CnHn'N: 8.91. Found: 3:69.

Preparation 2i--Metlzyl I,2=,3,4-;etrahydr0-1-naphlh0ate mixture of 14.3grams (0.081 mole) of l,2;3,4-tetra 'hydro-l-naphthoic acid and 160 milliliters of methanol saturated with hydrogen=chloride was heated under reflux for six hours. The excess methanol and hydrogen .chloriciewere removed by warming .under reduced pressure. The ,residue was --taken ,up .in benzene, .shaken awith- .agueoussodium bicarbonate, dried, over anhydrous magnesiumi sulfate, filtered and distilled. The y-ield-.of tester boiling cat Mil-.150 degrees centigrade at nineteen millimeters of .mercnry gpressure was 13.4 grams (86.6 percent of thetheoretical yield).

win-a mannertsimilarrtothat-of the above Preparation .2, other-testers of l ,2,3,4-tetrahydro-lnaphthoic acid may wbe prepared by tsubstituting an appropriate aicohoL-for Also, esters of l-indanecarboxylic acid can ahetprepared in a similar. manner.

'The'following examples .are; given to illustrate methods for usynthcsizingthe compounds 0f the present "inventionnbutvaret notto be construedas limiting.

5 cooled, Lpourediinto fiitymillilitersrof waterand made 'ZICldiCIWI lLh tdilute'i'hydrochloric acid. A-snrall amount of sdlid ((bisamide) was separated sbyzfiltration. The til- 1 trate was :extrac'tedxonce :with tether, ttreate'd with charcoal, filtered and made strongly alkaline. The .oil, .2-

tracted with ether. The ethereal eXtracLwas. dried over anhydrousmmagnesium :sulfate, filtered .andoacidified with etherealxhydrogen chloride. :The white, crystalline solid, 1. '2+ l-, 2,3.;4-tetrahydro-. lenaphthyl eimidazoline hydrochlo- ..ri'de, ,after recrystallization from alcohol, -melted "at 25.6- -257-degrees centigrade; -yield':3:4 wgrams (27.8 percent 05 thextheoretical yield) tArmlysis-r calculated for CrsI-InNiCl: N, 1l;84; Cl, 14.98. .Found: llt8l; l4f77.

Im'a manner -.siniilar to"that "of the above example other acid addition saltswsuc'h as,:'for examplejthe phosphate, phthalatc, sulfate, tartrate, nitrate, lactate, for

1 a mate, citrate, et cetera, may be prepared by contacting an ethereal solution of 2-(1,2,3,4-tetrahydro-1-naphthyl)-imidazoline with an ethereal solution of an appropriate acid and recovering the salt thus-formed. Also, quaternary ammonium salts may be prepared in a similar manner by contacting an ethereal solution of an appropriate quaternizing compound, such as, for example, methyl iodide, ethyl iodide, propyl chloride, butyl bromide, dimethyl sulfate, et cetera, with an ethereal solution of 2-(1,2,3,4-tetrahydro-1-naphthyl)-imidazoline and recovering the quaternary ammonium salt thusformed.

Pursuant to the procedure of the above example, the following salts were prepared from the free 2-(1,2,3,4- tetrahydrol-naphthyl) -imidazoline A mixture of five grams (0.0318 mole) of l,2,3,4- tetrahydro-l-naphthonitrile and sixteen grams (0.064 mole) of ethylenediamine mono-para-toluenesulfonate [prepared according to the procedure recited in Journal of the Chemical Society (1947), page 297] was heated at 200 to 210 degrees centigrade for two hours with oc casional swirling. After cooling, the reaction mixture was dissolved in fifty milliliters of dilute hydrochloric acid, and extracted with two 25-milliliter portions of ether to remove neutral material. The aqueous layer was'made strongly alkaline, and the solid material separated by filtration, washed with water and dried. After recrystallization from heptane-alcohol, there was obtained 4.9 grams (77 percent of the theoretical yield) of 2-( l,2,3,4-tetrahydro-1-naphthyl)-imidazoline, melting at 1 17-1 19 degrees centigrade.

Analysis.Calculated for Found: 13.77.

ciaHisNa: N, 13.98.

Example 3.--2-(1-indanyl)-imidaz0line hydrochloride 'dilute hydrochloric acid, extracted once with ether, and

the aqueous phase made strongly alkaline with sodium hydroxide. Extraction of this alkaline mixture with ether, drying of the ether extracts and acidification with ethereal hydrogen chloride yielded 8.5 grams of a crude brown powder. After recrystallization from alcohol, there was obtained five grams of 2-(1-indanyl)imidazoline hydrochloride, melting at 244-245 degrees centi grade.

Analysis.Calculated for C12H14N2HC1: Cl, 15.92. Found: 15.86.

In a manner similar to that of the foregoing Example 3, other acid addition salts of the indanyl compound may be prepared, than the hydrochloride, as by contact of various acids instead of hydrogen chloride with the alkaline aqueous solution. Among these acid addition salts which may be prepared, include, for example, the tartrate, nitrate, citrate, phosphate, sulfate, et cetera, as Well as quaternary ammonium salts, such as, for example, the methyl iodide, methyl bromide, propyl chlo-.

ride, dimethyl sulfate, et cetera.

e 11, v a i Example 4.--2(1,2,3,4-tetrahydro-1maphthyl) imidazaline hydrochloride A mixture of 540 grams (9.0 moles) of ethylenediamine, 270 grams (1.53 mole) of 1,2,3,4-tetrahydroalpha-naphthoic acid, and 360 milliliters (4.32 moles) of concentrated hydrochloric acid was introduced into a two-liter, three-necked'flask fitted with a thermometer, stirrer, and distillation take-oil. The mixture was distilled under a pressure of about twenty millimeters of mercury absolute until the temperature rose to 210 degrees centigrade. Thereafter, heating was continued under atmospheric pressure and when the temperature reached about 260 degrees centigrade, an exothermic reaction was initiated. The heat was then adjusted to maintain a reaction temperaturev of 275-280 degrees centigrade for 45 minutes and the mixture thereafter cooled to room temperature. Nine hundred milliliters of 4 Normal hydrochloric acid was added and the aqueous layer stirred with warming until a clear, brown solution resulted. This brown solution was made strongly alkaline with sodium hydroxide. The oil that separated solidified and was collected on a filter leaving filtrate A. The solid was dissolved in 370 milliliters of alcohol with warming, and the solution was treated with milliliters of concentrated hydrochloric acid with stirring and cooling. This acidified mixture was diluted with 300 milliliters of ether and chilled. The solid salt was collected and dried and thefiltrate concentrated to approximately 300 milliliters, diluted with 300 milliliters of ether and. thesalt which separated collected and dried. Filtrate A was extracted with ether, dried, acidified with alcoholic hydrogen chloride, and the salt which separated was collected and dried. There was thus obtained, when all the salt had been combined, 250 grams (69.3 percent of the theoretical yield) of 2-(1,2,3,4- tetrahydro-l-naphthyl)imidazoline hydrochloride, melting at 256-257 degrees centigrade.

Various modifications may be made in the present invention without departing from the spirit or scope thereof, and it is-to be understood that we limit ourselves only as defined in the appended claims.

We claim:

1. A compound selected from the group consisting of (at) those compounds having the formula:

wherein n is an integer from two to three inclusive, and (b) stable, non-toxic acid addition and quaternary ammonium salts thereof.

2. 2-(1,2,3,4-tctrahydro-l-naphthyl)imidazoline hydrochloride.

3. 2-(1,2,3,4-tetrahydro-l-naphthyl)imidazoline 4. 2-(indanyl)imidazoline hydrochloride.

5. 2-( 1,2,3,4-tetrahydro-l-naphthyl) imidazoline dihydrogen phosphate.

6. 2-(1,2,3,4-tetrahydro-l-naphthyl)imidazoline hydrobromide.

7. 2-(1,2,3,4-tetrahydro-l-naphthyl)imidazoline cyclohexylsulfamate.

8. 2-(1,2,3,4-tetrahydro-l-naphthyl)imidazoline bitartrate.

9. 2 (1,2,3,4 tetrahydro-l-naphthyl)imidazoline saccharinate.

10. 2 (1,2,3,4 1 tetrahydro 1 naphthyl)imidazoline methyl iodide.

References Cited inthe file of this patent UNITED STATES PATENTS 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF (A) THOSE COMPOUNDS HAVING THE FORMULA: 